A helping hand in Istanbul?

I'll be visiting Istanbul next month to attend an event. While I have booked myself a flight, in retrospect I'm afraid arriving at midnight isn't the best idea when you're new in town and don't know where to catch the buses from (if they still run at that hour!) or how far everything is from everything else in the city.

The train map was easy to find, however I couldn't find a bus map of the city. My lieu of attendance is to the east of Taksim where the train line doesn't run, so invariably I'll have to borad the bus. So too for wandering around the city.

If you live in Istanbul, could you please guide me to bus routes and timings please?

Also, do you have an idea whether the smaller hotels around Sultanahmet district have a late check-in time or run shuttle services to the airport usually? Of course I'll phone some hotels before booking in one today, but any general idea from forum members would be welcome.